Answer to Question #49875 in Mechanics | Relativity for tinu

Question

If a ball is thrown vertically upward from the roof of 58.8 m , when will it fall on the earth??
the solution is like this
let the upper direction is positive
then we can write

-h=ut-1/2gt^2 and t=6s .

my question is why h =10 is used here. i have thrown the ball from 58.8m upward. then it should have a height to the up and when it will fall downward then after crossing the roof it should have a height of 58.8m. so why in these case that upper height is not used .

my same question is also for projectile thrown from a height. there, also the upper height is not counted why?? why only the given height is used to solve the problems.